1. Field of the Invention
This invention relates to a method of weighing powder/chip and, more particularly, it relates to a method of feeding powder/chip to a weighing vessel efficiently and accurately.
2. Prior Art
As disclosed in Japanese Patent Laid-Open Publication No. 55-22178, a method is known in which cereal grains are weighed using a vertically shiftable conduit provided with an open end and arranged above a weighing vessel. The cereal grains fed in through the other end are mostly made to fall by gravity into the weighing vessel by tilting the conduit with the open end facing downward and then the conduit is turned to become horizontal and vibrated to let the residual grains spin out and fall into the vessel so that the grain may be weighed in an efficient way.
With the above described known weighing method, the conduit is tilted with the open end facing downward to dump a large volume of grains from the conduit at a time. However, the volume of grains discharged from the conduit by a single dumping motion varies depending on the state of the conduit and that of the object to be dumped and this variation in the dumped volume inevitably affects the subsequent vibration step of discharging the residual grains to give rise to fluctuations in the weighing accuracy and the weighing speed. Additionally, the step of discharging the residual grains by vibration is apt to be affected by external factors including ambient temperature and humidity to make the fluctuations in the weighing accuracy and the weighing speed even more remarkable, causing problems in efficiency and accuracy.
In view of the above identified problems of the prior art, it is therefore the object of the present invention to provide a method of weighing powder/chip that can feed the powder/chip from the conduit into the weighing vessel accurately and efficiently without being affected by the state of the conduit, that of the weighing vessel and that of the ambient air.